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D.J. Milton

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Drag marks in the Upper Precambrian Winnall Beds of central Australia were made by semibuoyant flexible objects at least 15 centimeters long, which presumably were algae. This find extends the range of such marks into the Precambrian era and supplements the discovery of microflora in the same sedimentary sequence.
Categories: Publication; Types: Citation; Tags: Science
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The Apollo 16 landing site in the lunar central highlands encompassed terra plains and adjacent mountainous areas of hilly and furrowed terra. These morphologic units, representing important terrane types in the lunar highlands, had been interpreted as volcanic on most premission geologic maps. However, it became apparent during the mission that there are indeed few or no volcanic rocks or landforms at the site but rather that the area is underlain by a wide variety of impact-generated breccias.
Categories: Publication; Types: Citation
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At orbit insertion on 14 November 1971 the Martian surface was largely obscured by a dust haze with an extinction optical depth that ranged from near unity in the south polar region to probably greater than 2 over most of the planet. The only features clearly visible were the south polar cap, one dark spot in Nix Olympica, and three dark spots in the Tharsis region. During the third week the atmosphere began to clear and surface visibility improved, but contrasts remained a fraction of their normal value. Each of the dark spots that apparently protrude through most of the dust-filled atmosphere has a crater or crater complex in its center. The craters are rimless and have featureless floors that, in the crater complexes,...
Categories: Publication; Types: Citation; Tags: Science
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Lonar Crater is a young meteorite impact crater emplaced in Deccan basalt. Data from 5 drillholes, a gravity network, and field mapping are used to reconstruct its original dimensions, delineate the nature of the pre-impact target rocks, and interpret the emplacement mode of the ejecta. Our estimates of the pre-erosion dimensions are: average diameter of 1710 m; average rim height of 40 m (30-35 m of rim rock uplift, 5-10 m of ejected debris); depth of 230-245 m (from rim crest to crater floor). The crater's circularity index is 0.9 and is unlikely to have been lower in the past. There are minor irregularities in the original crater floor (present sediment-breccia boundary) possibly due to incipient rebound effects....
Categories: Publication; Types: Citation; Tags: The Moon and the Planets
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